Power System Equivalent Parameters Tracking with PSO Based Optimal Quadratic Form Method

The Thevenin equivalent parameters seen at the point of common coupling (PCC) is an important parameter for power system planning and operation, voltage stability. This paper presents a novel algorithm of tracking the power system equivalent parameters online with PSO based optimal quadratic form method, using local measurements at PCC. The algorithm uses three coherent measurements at PCC for impedance estimation without requiring synchronized measurements, and a nonlinear algebraic equation is gotten with three point phasor data. In order to solve the nonlinear equations with good performance, the nonlinear algebraic equation is transformed to an optimal quadratic form then. Later, an optimal quadratic form method based on particle swarm optimization (PSO) is provided for estimating the parameters by constructing the objective function of PSO according to quadratic form. Later, online tracking of equivalent parameters is realized by dynamic PSO estimation method. Verification studies, including calculating of static and dynamic equivalent parameters of the power system, are provided to verify the algorithm with Matlab/Simlink. Moreover, noise condition and error of measurements are investigated. The proposed algorithm has some advantages of convergence, precision and simplicity.